Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

United States

Thermal simulation tools are an essential element in the design of low energy / low carbon buildings. However, they have made little impact on the building design community, despite legislation and industrial and technological development requiring more performance oriented and energy efficient buildings. Although this is a multi-faceted challenge, the research methods used to investigate and address it tend to lack the necessary richness and interdisciplinarity. Current outputs from simulation tools tend to be unrelated to concepts that are meaningful to the building designer and incompatible with his/her constructivist / experimental / 'learning by doing' way of approaching problem-solving. Developers are rarely provided with adequate information about how simulation results can be used to inform design decisions. Consequently, responses to the problem tend to be interpretations of what the simulation community assumes the building designer needs. These responses tend to be based on research methods that are ineffective in matching needs with their appropriate solutions. Research methods such as interviews, structured on-line surveys, reports of specific case studies and observations from working in collaboration with building designers simply describe the problem without showing how it can be solved. Even though much has been achieved in improving input interfaces and facilitating modelling in the early design stages (connecting SketchUp with EnergyPlus via OpenStudio, the set up of AutoDesk Project Vasari, etc.), there is still much to be done about the content and format of building thermal simulation results for them to be effectively used in design decision making. The displays of time-series graphs and tables with temperatures and loads connected to surfaces and volumes are meaningless for building designers to use. Designers need results that effectively connect these temperatures and loads with the building elements they are manipulating. This research proposes to focus on the gap that exists between the output information from simulation tools and what is actually needed for building designers to undertake informed design decisions when designing energy-efficient low carbon buildings - the gap that prevents simulation tools from being better integrated throughout the building design process. Hence, it aims to generate procedures to produce post-processed information and data representation systems that are meaningful to building designers. These procedures and outputs will be illustrated by a series of tested and validated examples developed through interdisciplinary collaboration. As suggested, proper collaboration between building design researchers and building simulation software researchers is essential to acknowledge and brings together the different ways these two disciplines interpret and manipulate building thermal physics. Moreover, the approach creates opportunities for a different research method to be explored. The method consists in inviting the building designer to propose what he/she thinks would be useful building physics information to support his/her design decisions when presented with a design task specifically tailored to facilitate the extraction of this information. Propositions include parameters, indices, diagrammatic and multimodal ways of representing results as well as possibilities of undertaking design changes. This method, not used before in this research area, aims to ensure that simulation tools will be consonant with the way of thinking and modus operandi of the designer, in ways that will mitigate current resistance to incorporating simulation results in design decision making.

The power demand of the world is staggering! In 2014, the power requirements of the earth were just over 17 TW, and with an ever increasing population, this value is growing every year. It is clear then, that one of greatest challenges facing humanity is the need for sustainable and clean sources of power. Sunlight provides this in abundance, and in recent years there has been a drive to utilise this resource, through the manufacture and installation of photovoltaics (PV) worldwide. The PV industry has experienced massive growth in the last 10 years, in part due to governmental support in the form of subsidies; however this support will not last forever. It is important that once subsidies have disappeared, the installation of PV around the world remains constant, and continues to deliver clean power to the population. Whilst the majority of the installed capacity is based on well-established silicon based solar cells, more and more cost savings can be found in thin film PV technologies, where cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) solar cells deposited using vacuum deposition methods represent the leading materials which have successfully moved from lab to industry. However, cost reduction is still key, and to reduce costs further, it is important to move away from expensive methods involving vacuum deposition techniques, and towards devices produced using solution chemistry under atmospheric conditions. However, the deposition of thin film solar cells from solution is not easy. Typically, solutions are prepared by dissolving common metal salts in standard solvents, which are then cast onto a supporting substrate and annealed. As a result, undesired impurities from the salt are often included within the film (such as chlorine or oxygen), which is detrimental to solar cell performance. An alternative approach, which has been successfully developed by researchers at IBM, is to dissolve chalcogenides (such as copper sulphide, indium selenide and gallium selenide) in hydrazine, and produce the solar cell from this solution. In this case, hydrazine has been used as it had been the only known solvent to successfully dissolve chalcogenide materials at room temperature. Using this method, it is possible to fabricate CIGS thin films, without inclusion of detrimental impurities, since all the desired constituent elements are in the starting precursors (namely copper, indium, gallium, selenium and sulphur), with no foreign contaminants. Whilst this method has produced the highest solution processed thin film solar cells to date, hydrazine is a highly toxic, carcinogenic and explosive solvent, which makes up-scaling this technique very difficult. With this in mind, this project aims to fabricate highly efficient thin film CIGS solar cells, using the benefits of chalcogenide starting precursors (i.e. no detrimental impurities), whilst using a safer solvent combination without the use of hydrazine. Recent work by the PI at Loughborough has shown that it is possible to dissolve chalcogenides for use in CIGS thin film growth in a solvent combining an amine and a thiol source. The solvents can be used easily without the need of sophisticated protection equipment; they can be used in ambient atmosphere (hydrazine requires a nitrogen filled glove box); and they do not suffer from strict control laws unlike that of hydrazine (anhydrous hydrazine can not be purchased in the UK). The aim of the project is to fabricate 12-14% CIGS solar cells using the technique, combining the benefits of low toxicity solvents with the pure starting precursors used in the hydrazine method.

The development of renewable energy sources is an urgent problem and so large that many technologies will contribute. Solar photovoltaics can be expected to play a major role because of the abundance of solar energy, and the convenience of electricity as an energy source, but at present they contribute only a tiny fraction of the world's energy supply (e.g. ca. 0.1% in the US, according to the US Institute for Energy Research). The major reason for the very limited uptake is that current solar cells are much more expensive than generating power from fossil fuels. Organic semiconductors have the potential to solve this problem by providing a route to much lower cost solar cells. Organic semiconductors are pi-conjugated molecules and polymers, that can be processed from solution via low cost/high volume deposition techniques such as spin-coating, roll-to-roll processing and ink-jet and screen printing. This means that they can be used to make flexible thin film devices that are lightweight and portable. We propose to develop new organic solar cell materials building on our promising initial results from novel cross-shaped molecules. The proposed materials have well-defined structures that pack together efficiently, giving improved charge transport. The key idea is to control this packing of materials so that they will "self-assemble" into the desired arrangement for efficient solar cells. To achieve this we will bring together teams of physicists and chemists and collaborate with leading groups at the National Renewable Energy Laboratory and Imperial College London.